Encryption-at-Rest refers to the practice of encrypting data while it is stored on a physical medium, such as a hard drive, SSD, or cloud storage. The primary goal of encryption-at-rest is to protect stored data from unauthorized access in case the storage medium is lost, stolen, or compromised. By encrypting data at rest, organizations can ensure that even if a malicious actor gains access to the physical storage, they cannot read or use the data without the appropriate decryption key.

Encryption-at-rest is a critical component of data security, especially in industries that handle sensitive information such as healthcare, finance, and government sectors. It is often required to comply with data protection regulations like GDPR (General Data Protection Regulation), HIPAA (Health Insurance Portability and Accountability Act), and PCI-DSS (Payment Card Industry Data Security Standard).

There are several ways to implement encryption-at-rest. One common method is full disk encryption (FDE), where the entire disk or storage volume is encrypted. This method ensures that all data on the disk, including system files, user data, and temporary files, is protected. Another approach is file-level encryption, which encrypts individual files or folders. This method offers more granular control, allowing specific sensitive files to be encrypted without affecting other parts of the system.

Cloud service providers such as AWS, Google Cloud, and Azure often provide built-in encryption-at-rest capabilities for their storage services, allowing users to encrypt data stored in databases, file systems, and object storage. These services typically manage encryption keys using systems like AWS Key Management Service (KMS), making encryption more accessible and easier to manage for cloud-based applications.

In summary, encryption-at-rest is a fundamental practice for securing stored data from unauthorized access. By encrypting data while it is stored, organizations can protect sensitive information, comply with regulatory requirements, and reduce the risk of data breaches.